The dental bar is an important piece in the implant-based dental restorations for partially or fully edentulous patients. Implant-based dental restorations have many advantages over standard removable dental restorations since the implants can prevent the loss of jawbones, especially in older patients, help to restore facial features, and enable the patients to get firm bites. A critical step in dental restoration is the fabrication of the dental bar on which the ceramic denture sits. A dental bar is patient-specific, i.e., a particular dental bar is outfitted for a particular patient as each patient's jaw is unique, and needs to be fitting firmly in a patient's mouth and confirming to the shape of the patient's gingival surface. Thus, the design of a dental bar is a crucial step in the fabrication of the dental bar and eventually success of the dental restoration.
Traditionally, designing of a dental bar has been done manually by a dentist, which is a lengthy and labor intensive process and requires high levels of artistic work on the part of the dentist. There have been attempts to develop methods and systems towards automated design and fabrication of dental bars, however, with very limited successes. Currently, the commercially available “automated” dental restoration systems are only capable of making restorations for single tooth, not for edentulous patients requiring multiple teeth restorations.
For example, CEREC® is a commercially available CAD/CAM system for design and fabrication of ceramic dental restorations (http://www.cereconline.com). The system consists of a data acquisition device (infrared camera), a milling machine unit, and a software module that generates the missing part of a patient's tooth. A dentist can use the system for crowns, fillings, and single-tooth restorations.
Procera® technology is another commercially available CAD/CAM process that involves computer generated copings to provide precision fit within the acceptable level according to the standards of American Dental Association (http://www.nobelbiocare.com). Prior to this technology all-ceramic restorations had to be bonded into place using resin cements, due to lack of strength and marginal integrity of the restorations. Crown restorations for single tooth produced by Procera® have been shown to be within the clinically accepted range for marginal opening gap dimensions.
The inventors' lab previously attempted to develop an automated process for dental bar design with limited success. The previous attempt is documented in Mr. Po-Wen Yang's thesis tilted “Feasibility Study of 3-D Cylinder Data Fitting on the Bar-retained Removeable Overdenture Design.”
Therefore, it is desirable to develop a novel, automated method and system to design a dental bar for dental restorations.